Lockable core barrel head for drilling system and survey instrument assembly provided with a connection link for arrangement in a drilling system

ABSTRACT

Core barrel head for connection to a core barrel for collecting core samples, and for connection to a latch assembly, to mount a drill assembly in a bore hole, with a sleeve for carrying the inner tube. A controllable locking device is arranged inside the core barrel head for locking the sleeve in a fixed rotational position relatively to the attached latch assembly, to allow measurement of the inclination and the orientation of the core. The invention also includes a survey instrument assembly provided with a connection link for connection to a spearhead, drill pipe, latch assembly, core barrel head or other drilling or geotechnical equipment.

FIELD OF INVENTION

The invention relates to a core barrel head for a wire line operated drilling system used for taking core samples of bedrock, as described in the introduction to claim 1.

The invention also relates to a survey instrument assembly provided with a connection link for arrangement in a drilling system, as described in the introduction to claim 7. Especially a survey instrument assembly provided with a connection link for connection to a spearhead, drill pipe, latch assembly, core barrel head or other drilling or geotechnical equipment.

BACKGROUND

When taking core samples of bedrock using core drilling equipment, knowing bore hole trajectory (depth, azimuth and inclination) as well as rotational orientation of the core sample are vital information to be able to process the data given by the collected core.

Existing systems for reading the core sample orientation demands that total length between the core catcher and latch unit or free space/length inside the inner tube is reduced to accommodate the instrumentation.

Existing systems for reading borehole inclination demands that a separate survey instrument is lowered inside the drill string by wire.

OBJECT

The main object of the invention is to improve prior art core drilling technology. More specifically it is an object to provide a core barrel head, allowing accurate reading and logging of the core sample rotational orientation without increasing the total length between the core catcher and latch unit or reduce free space/length inside the inner tube.

The invention introduce to the marked a specially designed barrel head that can be locked/unlocked in any positions, more specifically locked for axial rotation, making it possible to do down hole readings of core sample rotational orientation, as well as the orientation of other down hole applications, without increasing the total length between the core catcher and latch unit or reduce free space/length inside the inner tube.

A further object of this invention is to allow the recording of borehole and core sample inclination, without need of making a separate survey-run.

An object of the invention is to provide a survey instrument assembly provided with a connection link arranged for connection to a spearhead or spearhead assembly.

Another object of the invention is to provide a survey instrument assembly provided with a connection link arranged for connection to a drill pipe, latch assembly, core barrel head or other drilling or geotechnical equipment.

THE INVENTION

A core barrel head according to the invention is described in claim 1. Advantageous features of the core barrel head according to the invention are described in claims 2 to 6.

A survey instrument assembly according to the invention is described in claim 7. Advantageous features of the survey instrument are described in claims 8-14.

For performing core drilling there is provided a first aspect of the invention in the form of a core barrel head assembly provided with a latch unit equipped with instruments and mechanisms to access the inclination and rotational orientation of the core sample.

According to the first aspect there is provided a core barrel head for connection to a core barrel and inner tube for collecting core samples, and for connection to a latch assembly, with a sleeve for carrying the inner tube. The core barrel head further includes a controllable locking device arranged inside the core barrel head for locking the sleeve in a fixed rotational position relatively to the latch assembly, to allow measurement of the rotational orientation of the core samples.

According to the first aspect the locking device is provided with at least one movable locking pad, to engage the inner wall of the sleeve.

According to a second aspect of the invention the locking device comprises a locking element, which is movable relatively to a radial and/or axial face, to provide a locking between the sleeve and a spindle carried by the latch assembly.

According to a third aspect the locking pad(s) is/are arranged tiltable instead of being rotational or axially movable.

According to a fourth aspect of the invention the engagement/disengagement of the locking device is operated mechanically by the latch unit.

According to a fifth aspect of the invention the engagement/disengagement of the locking element is hydraulically operated.

According to a sixth aspect of the invention a survey instrument assembly is attached at the upper side of the latch assembly.

For performing core drilling, there is provided a seventh aspect of the invention in the form of a survey instrument assembly provided with a connection link at a lower end arranged for connection to a spearhead, drill pipe, latch assembly, core barrel head or other drilling or geotechnical equipment.

The connection link is at an upper end provided with means for arrangement to the survey instrument assembly, such as a protruding element provided threads.

For connection to a spearhead the connection link is at a lower end of the body provided with a quick snap connection adapted for retaining the spearhead.

For connection to a drill pipe, latch assembly, core barrel head or other drilling or geotechnical equipment the connection link is at a lower end provided with a radial hole, via which hole a drill pipe, latch assembly, core barrel head or other drilling or geotechnical equipment can be connected by insertion of a pin in the radial hole.

The survey instrument assembly is at an upper end provided with means, such as a spearhead point, for attachment to a wire line or a radial hole for attachment to suitable means for operating the survey instrument assembly.

According to an eight aspect of the invention the connection means at the lower end of the connection link is a quick-snap connection provided with at claw for accommodating the spearhead and secure retaining of this, and for locking axial and rotational movement of this.

According to a ninth aspect of the invention the claw at the lower end of the connection link is provided with at least one claw arm being movable about an axes being offset from a central axis of the body.

According to a tenth aspect of the invention claw at the lower end of the connection link is provided with two arms being movable about parallel axes being offset from a central axis of the body.

According to an eleventh aspect of the invention the claw arms at the lower end of the connection link are spring-biased and designed for retaining the spearhead.

Further advantageous features and details of the invention will appear from the following example description.

LIST OF FIGURES

FIG. 1 is showing a side view of a drilling assembly for wire line suspension, with a core barrel head according to the invention at the lower end,

FIG. 2 is showing an axial section of an embodiment of a lockable core barrel head according to the invention, for carrying an inner tube (not shown),

FIG. 3 is showing a cross section through a further embodiment of a core barrel head according to the invention, with an alternative locking means,

FIG. 4 show a side view of a survey instrument assembly for wire line suspension, with a connection link provided with a quick snap connection according to the invention at the lower end,

FIG. 5 a is showing a perspective view of a connection link provided with a quick snap connection according to the invention,

FIG. 5 b is showing a cross sectional view of a the connection link in FIG. 5 a, and

FIG. 5 c is showing a perspective view of an alternative connection link.

DESCRIPTION OF PREFERRED EXAMPLES

FIG. 1 shows at the upper end of a drilling system 10 a spearhead point 11 for attachment to a wire line during operation, a survey instrument assembly 12 containing the circuits and units needed for logging the position of the drilling assembly, including the inclination and the rotational orientation of the core samples.

A communication port 13 is arranged at the lower end of the survey instrument assembly 12. Following the communication port 13 is a latch assembly 14 with a latch housing 15 and a pair of latch elements 16 and 17. The latch elements 16 and 17 are operated by prior art technology to lock the drilling head assembly inside the core barrel.

At the lower end of the latch assembly 14 an axial threaded hole indicated at 18 is arranged, for the upper threaded end 19 of a core barrel head 20 according to the invention. The core barrel head 20 is locked with a locking nut 21. Through the threaded hole 18, access to the interior of the latch assembly 14 is provided, to get an input for controlling the core barrel head according to the invention, as will be described.

FIG. 2 shows the core barrel head 20 of FIG. 1. Its main parts are a cylindrical spindle 22 with the treaded end 19 and with an axial bore 23 for a locking bolt 24. The spindle 22 is carrying a spindle bushing 25, a trust bearing 26 being arranged between the upper part of the spindle and the spindle bushing 25. The spindle bushing 25 is connected to a spindle sleeve 27 with a threaded connection 28. At the lower end of the spindle sleeve 27, there is a threaded bore 29 for carrying an inner tube collecting core samples. More structural and functional details of this assembly are described in the following.

At the upper end of the axial bore 23 of the spindle 22 a slider or piston 30 is arranged. The piston 30 has a threaded bore 31 to be attached to the upper end of the locking bolt 24. The upper end of the piston 30 carries an adjustment screw 32 protruding into the latch unit 14. The adjustment screw 32 and thus the locking bolt 24 are operated from the latch unit 14.

The locking bolt 24 is extending through the bore 23 in the spindle 22, and into a bore 33 in the spindle sleeve 27. In the bore 33 a hub 34 is arranged. The hub 34 is carried by the lower end of the spindle 22 and is having a central axial bore 35 for the locking bolt 24. In two opposing radial slots 36, 37, two locking pads 38, 39 are arranged. The inner end of the locking pads 38, 39 are engaging a conical neck 40 on the locking bolt 24 with a ball 41 as connection.

When the locking bolt 24 is not engaged by the latch unit, it is lifted to an upper position by a screw spring 42 under the piston 30. In this position, the conical neck 40 will expand the locking pads 38, 39 into engagement with splines 43 in the surrounding bore and thus lock the sleeve 27 in relation to the spindle. The locking is facilitated by mating splines on the free end of the locking pads 38, 39 engaged with splines 43 on the surrounding wall of the bore 33.

When the locking bolt 24 is engaged by the latch assembly 14, the locking pads 38, 39 are withdrawn from the splines 43. In this position, the spindle bushing 25 and the spindle sleeve 27 are allowed to rotate freely.

In FIG. 3 an alternative embodiment of the invention is shown, with a core barrel head assembly 44 based on a sleeve 45. The lower end of the sleeve 45 is accommodating a piston 46 and a downward projecting piston rod 47 linked to the sleeve 45 with a cross pin 48. The piston rod 47 carries a lower screw spring 49 compressed between the piston 46 and a stop dish 50 locked with a locking ring 51 to the inner wall of the sleeve 45. The screw spring 49 will urge the piston 46 towards an upper position. The purpose of this arrangement will appear from the following description.

A stack of four roller bearings 52, 53, 54, 55 is carried by a spindle 56. The spindle 56 is protruding at the upper end of the core barrel head 44. The top of the spindle 56 is provided with a flange 57 and a crossing hole 58. The purpose of these parts is to connect the spindle 56 to the latch unit of FIG. 1.

The spindle 56 is at the lower end carrying a cylindrical nut 59 provided with a friction dish 60 facing the upper end of the piston 46. The cylindrical nut 59 is fixed in an end position of the spindle 56.

An upper screw spring 61 is arranged behind the nut 59 for allowing the sleeve 45 to move forward between the spindle 56 and sleeve 45 when the pull force exceeds a certain load.

Under the force of the lower screw spring 49, the upper end of the piston 46 is pressed against the friction dish 60 attached to the cylindrical nut 59. The faces of the elements involved in the frictional locking may be suitably errated.

The wall of the sleeve 45 has two openings 62, 63 for access of drilling fluid. When under pressure, the drilling fluid will act upon the piston 46 and urge it downward, releasing the frictional locking of the sleeve 45. When the piston 46 is engaged, the sleeve 45 will be free to rotate independently of the latch unit.

Alternative Locking Mechanisms

The hub 34 of FIG. 2 may have alternative embodiments. Any locking means which can be operated by mechanical or hydraulic pressure may be utilized. The locking pads 38, 39 may be replaced by a ring of compressible, expandable material being expandable by the force from a screw spring and releasable by hydraulic fluid.

The locking pads 38, 39 may be arranged tiltable instead of being rotational or axially movable.

The piston 30 may also be operated by restricting the waterflow, thus building up a pressure inside the latch unit 14.

The spindle 56 of FIG. 3 may have a longitudinal bore, corresponding to bore 23, extending throughout the spindle and through the friction dish 60. In an alternative embodiment, the longitudinal bore may accommodate a locking bolt corresponding to the locking bolt 24 of the embodiment in FIG. 2. The latch unit may engage this locking bolt to depress the piston 46. This will be an alternative way of unlocking of the friction means.

Novel Survey Instrument Assembly

Reference is now made to FIG. 4 which shows a survey instrument assembly 12 provided with a spearhead point 11 for attachment to a wire line during operation. The survey instrument assembly 12 may also be provided with other suitable means replacing the spearhead point for operation of the survey instrument assembly 12. A survey instrument assembly 12 contains circuits and units needed for logging the position of a drilling assembly, including the inclination and the rotational orientation of core samples or other geotechnical instruments. A communication port 13 is arranged at the lower end of the survey instrument assembly 12.

A survey instrument assembly 12 according to the invention further includes a connection link 70 arranged for connection to a spearhead point 11 or spearhead assembly, as shown in FIGS. 5 a-b, or to a drill pipe, latch assembly, core barrel head or other drilling or geotechnical equipment as shown in FIG. 5 c.

Reference is now made to FIGS. 5 a-b which show details of a connection link 70 arranged for connection to a spearhead 11. The connection link 70 is formed by a mainly elongated body 71 which at its upper end is provided with means for connection to the survey instrument assembly 12, such as a protruding element 72 provided with threads 73 adapted to a threaded hole at the lower end of the survey assembly 12. At a lower end of the body 71 the connection link 70 is provided with means for accommodating and retaining the spearhead point 11, preferably in the form of a quick snap connection. A quick snap connection is, for example, provided by means of a claw 74 arranged for accommodating and secure retaining of the spearhead point 11, and for locking the axial and rotational movement of this. In the example there is shown a claw 74 including two claw arms 75 which are movable about two parallel axes 76 being offset from the central axis of the body 71. The claw arms 75 are preferably spring-biased and designed for retaining the spearhead point 11, and for locking the axial and rotational movement of this.

Reference is now made to FIG. 5 c which shows details of a connection link 70 adapted for connection to a drill pipe, latch assembly 14, core barrel head 20 or other drilling or geotechnical equipment. The connection link 70 is here formed by a solid mainly elongated body 71 which at its upper end is provided with means for connection to the survey instrument assembly 12, such as a protruding element 72 provided with threads 73 adapted to a threaded hole provided at a lower end of the survey assembly 12. At a lower end of the solid body 71 the connection link 70 is provided with connection means adapted to connection means of a drill pipe, latch assembly 14, core barrel head 20 or other drilling or geotechnical equipment for connection thereto. The connection means are in the shown example a radial hole 77 for insertion of a pin for secure connection to corresponding holes in a drill pipe, latch assembly, core barrel head 20 or other drilling or geotechnical equipment.

By using a survey instrument assembly 12 provided with a connection link 70 as described above it will be possible to always have the survey instrument assembly 12 close to the drilling assembly, which is preferable for the accuracy of the drilling operation.

By use of a survey instrument assembly 12 provided with a connection link 70 according to the invention the drill operation will become more rapid, due to the number of separate survey runs are reduced, as well as one will have better control of bore hole trajectory by continuous logging of bore hole trajectory. In other words the survey instrument assembly 12 provided with a connection link 70 according to the invention provides MWD—Measure while Drilling—operation.

The above described connection link 70 may be used with the core barrel head 20 or without the core barrel head 20.

Modifications

The survey instrument assembly provided with a connection link may be provided with other drilling equipment, such as packers or wedges, or geotechnical instruments.

The claw of the connection link can include only one claw arm if the body is adapted with means for accommodating and retaining the spearhead, and for locked axial and rotational movement of this

The means for connection of the survey instrument assembly to the connection link may be adapted to other suitable connection means.

The means for connection of a drill pipe, latch assembly, core barrel head or other drilling or geotechnical equipment to the connection link may be adapted to other suitable connection means.

LIST OF REFERENCE NUMERALS

10 drilling head assembly

11 spearhead point

12 survey instrument assembly

13 communication port assembly

14 latch assembly

15 latch housing

16, 17 latch elements

18 hole in latch assembly

19 threaded end

20 core barrel head

21 locking nut

22 spindle

23 axial bore

24 locking bolt

25 spindle bushing

26 thrust bearing

27 spindle sleeve

28 threaded connection

29 threaded bore

30 piston

31 threaded bore

32 adjustment screw

33 bore in the spindle sleeve

34 hub

35 axial bore

36, 37 slots for locking pads

38, 39 locking pads

40 conical neck

41 ball

42 screw spring

43 splines

44 core barrel head assembly

45 sleeve

46 piston

47 piston rod

48 cross pin

49 lower screw spring

50 stop dish

51 locking ring

52-55 roller bearings

56 spindle

57 flange

58 crossing hole

60 friction dish

61 upper screw spring

62, 63 openings

70 connection link

71 body

72 protruding element

73 threads

74 claw

75 claw arms

76 parallel axes

77 radial hole 

1. Core barrel head (20) for connection to a core barrel for collecting core samples, and for connection to a latch assembly (14), with a sleeve (27) for carrying an inner tube, characterized in that a controllable locking device (38, 39; 60) is arranged inside the core barrel head (20) for locking the sleeve (27) in a fixed rotational position relatively to the latch assembly (14), to allow measurement of the rotational orientation of the core samples.
 2. Core barrel head according to claim 1, characterized in that the locking device is provided with at least one movable locking pad (38, 39), to engage the inner wall of the sleeve (27).
 3. Core barrel head according to claim 1, characterized in that the locking device comprises a locking element (60), which is movable relatively to a radial and/or axial face, to provide locking between the sleeve (45) and a spindle (22, 56) carried by the latch assembly (14).
 4. Core barrel head according to claim 2, characterized in that engagement/disengagement of the locking device (38, 39) is operated mechanically by the latch unit (14).
 5. Core barrel head according to claim 1, characterized in that the engagement/disengagement of the locking element (60) is hydraulically operated.
 6. Core barrel head according to claim 1, characterized in that a survey instrument assembly (12) is attached at the upper side of the latch assembly (14).
 7. Survey instrument assembly (12) containing circuits and units needed for logging the position of a drilling assembly, including the inclination and the rotational orientation of core samples or other geotechnical instruments, which survey instrument assembly at a lower end is provide with a connection means and at an upper end is provided with means (11) for connection to a wire line or other suitable means for operating a drilling assembly, characterized in that the survey instrument assembly (12) is provided with a connection link (70) at a lower end of the survey instrument assembly (12), which connection link (70) includes a body (71) which at an upper end thereof is provided with connection means (72) for connection to the survey instrument assembly (12) and at a lower end thereof is provided with connection means (74, 77) for connection to a spearhead (11), drill pipe, latch assembly (14), core barrel head (20) or other drilling or geotechnical equipment.
 8. Survey instrument assembly according to claim 7, characterized in that connection means (72) for connection to the survey instrument assembly (12) is a protruding element provided with threads (73) adapted to a threaded hole provided at a lower end of the survey instrument assembly (12).
 9. Survey instrument assembly according to claim 7, characterized in that the connection means (74) at the lower end of the body (102) for connection to a spearhead (11) is a claw arranged for accommodating and retaining the spearhead (11), and for locking axial and rotational movement of this.
 10. Survey instrument assembly according to claim 9, characterized in that the claw includes two claw arms (75), which arms (75) are movable about two parallel axes (76) being offset from a central axis of the body (71).
 11. Survey instrument assembly according to claim 10, characterized in that the claw arms (76) are spring-biased and designed for retaining the spearhead (11), and for locking axial and rotational movement of this.
 12. Survey instrument assembly according to claim 9, characterized in that the claw includes one claw arm (76) and that the body (71) is adapted for together with the claw arm (76) to accommodate and secure retain the spearhead (11), and for locking axial and rotational movement of this.
 13. Survey instrument assembly according to claim 7, characterized in that the body (71) is a solid body and the connection means (77) at the lower end are adapted to connection means of a drill pipe, latch assembly (14), core barrel (20) or other drilling or geotechnical equipment for connection thereto.
 14. Survey instrument assembly according to claim 13, characterized in that the connection means (77) at the lower end of the solid body (71) is a radial hole via which a drill pipe, latch assembly (14), core barrel (20) or other drilling or geotechnical equipment can be connected by insertion of a pin. 